17.—(1) Regulation 16 does not apply to any association if the main object of the association is to enable the benefits of membership (whatever they may be) to be enjoyed by persons of a particular sexual orientation.
(2) In determining whether that is the main object of an association regard shall be had to the essential character of the association and to all relevant circumstances including, in particular, the extent to which the affairs of the association are so conducted that the persons primarily enjoying the benefits of membership are of the sexual orientation in question.